An example of a climate control system of the prior art is seen in FIG. 1. The system comprises an electronic microprocessor controller 26 which receives a temperature signal from an interior air temperature sensor 28. It also receives signals from a solar heat sensor 30 and an ambient air temperature sensor 32. The controller 26 will develop a voltage, as shown at 34, for controlling the speed of the blower 36 as air is passed by the blower over an evaporator 38 and a heater core 40. In a conventional fashion, the air flow that passes over the heater core 40 can be controlled by a blend door 42, the opening of which is controlled by an air mix controller 44. The processor 26 in a conventional fashion will activate the blend door as indicated schematically at 46.
Air is distributed to the upper control panel area as shown at 48 or to the lower floor area of the vehicle as shown at 50, depending upon the position of door 52, which is under the control of an air mode controller 54. The controller 26 activates the air mode controller 54 as shown at 56.
The vehicle operator may set the desired temperature with a conventional control head, the output of which is distributed to the controller as an input.
Intake air mass flow is also determined by the electronic controller 26, as indicated by control line 60.
The electronic controller may be one of a variety of known digital microprocessors (e.g., an 8-bit, single-chip microcomputer). It includes a read-only memory (ROM) in which the heat flux control equation is stored. It has the usual random-access memory registers (RAM) that receive information from the sensors before it is looked upby the central processor unit (CPU) and used by the CPU logic to act upon the stored equation in ROM to produce an output for the driver circuits. In known fashion, the processor monitors the sensor information during successive control loops as it performs sequentially the process steps.
The interior heat content for an automotive vehicle is affected by a number of variables including but not limited to the sun load heat flux (kW/m2), the effective glass area capable of transmitting a solar heat load, the heat generated by passengers and electronic devices within the vehicle passenger compartment, the ambient temperature of the air surrounding the vehicle, the mass air flow rate (enthalpy rate per degree), the average outlet temperature of the air conditioning system, and the heat transfer coefficient for heat transfer between the passenger compartment and the ambient air. An automotive temperature control system should take the thermodynamic interaction of these variables into account in an attempt to maintain a target interior temperature in the most effective way.
U.S. Pat. No. 5,832,990, which was awarded to the present inventor, is an example of an automatic climate control system for vehicles that respond to the above mentioned variables, including airflow. The ""990 patent teaches an automatic interior temperature control system for an automotive vehicle capable of controlling heat flux in response to changes in (but not limited to) ambient temperature, outlet temperature, sun load and air flow by taking into account the relationship between these four variables in accordance with thermodynamic principles wherein an adjustment in heat flux corrects an interior temperature error. U.S. Pat. Nos. 6,272,871 and 6,272,873 are examples of prior art air conditioning systems, the content of which is incorporated herein by reference.
There is a desire to automatically control the temperature in two zones inside a vehicle while an adjustment in heat flux corrects an interior temperature error. Some climate control algorithms calculate two separate outlet temperatures that are based on empirically determined factors or gains applied to various sensor inputs that depend on expensive trial and error vehicle level testing. These algorithms do not take into account heat flow considerations, or at best minimize the heat flow considerations due to the absence of the direct influence of system airflow in the calculation method. This omission creates error and considerable compromise in the task of achieving an appropriate climate for each zone, particularly when the target zone temperatures differ.
This is a problem because in a typical operating environment, for example, either more or less cooling is required depending upon whether the vehicle is unshaded or shaded. The previous dual zone climate control systems attempt to adjust the outlet temperatures to achieve a target interior temperature without taking into account the effect of air flow in the control of total heat load. They are designed to affect adjustment in the temperature of the system outlet, but they do not provide a quantifiable and significant change in the total heat flux itself as the system attempts to achieve a target interior temperature.
The present inventor has discovered a dual zone automatic climate control algorithm utilizing a heat flux analysis that overcomes the deficiencies in the prior art. The present inventor has discovered a set of control equations for a dual zone (by way of example and not by limitation: left-right) using energy balance considerations for the thermal influence in the vehicle cabin. The factor of airflow is included directly in the calculations of the two outlet temperatures. This considerably simplifies the development process and often inherently corrects errors that are generated by neglecting the direct influence of airflow. A logic system utilizing the equations addresses thermal balance of two zones that may have a single interior temperature sensor (for low cost reasons) to ones with multiple interior sensors. Further, the present invention can provide for a single airflow source for the system, but is not limited to such a design. In such a scenario, a primary zone and a secondary zone is defined for the purpose of control priority. The primary zone can be used to govern the transient (overall cabin temperature correction) and set up the total system airflow. The secondary zone can be provided with a stabilization enhancement logic that may provide increases to the system airflow, only when the full cold or full hot outlet temperatures are not sufficient for that zone""s temperature achievement. In addition, the secondary zone can be provided with transient enhancement logic, which creates a temporary outlet temperature overshoot that depends on the rate of this zone""s temperature target adjustment.
In one embodiment of the present invention, there is a method for automatically controlling the climate in a plurality of climate control zones of a cabin of an automobile comprising at least a first zone and a second zone having a temperature sensor located in the first zone and a conditioned air outlet vent in each of the zones, the method comprising, obtaining a target temperature value for the first zone and the second zone; obtaining a first zone temperature value estimate from the sensor in the first zone; obtaining an ambient air temperature value; obtaining a sun load heat flux value for at least one of the first zone and the second zone; obtaining a first zone gain factor value based at least on the first zone temperature value estimate; automatically determining the outlet temperatures and the mass flow rates of the first zone outlet and the second zone outlet based at least on the above obtained values and on a conduction/convection heat transfer coefficient between the cabin and the ambient air, an effective glass area for solar load transmission, a zone air crossover influence factor, and predetermined constraints on the relationship of the outlet temperatures and air flow, wherein the zone air crossover influence factor is a factor based on blending of the air in the cabin; and providing conditioned air to the cabin from the first zone outlet and the second zone outlet at outlet temperatures and mass flow rates correlating to the determined outlet temperatures and mass flow rates.
In another embodiment of the present invention there is a method wherein the zone air crossover influence factor is variable and depends on an air distribution mode.
In another embodiment of the present invention the method further includes calculating an error term and subtracting it from the second zone outlet temperature to establish a new second zone outlet temperature, the error term comprising a value based on the first zone target temperature value, the first zone temperature value estimate, the mass air flow rate of the second zone outlet, and a second zone gain factor value based at least on the first zone temperature value estimate, wherein the conditioned air provided to the second zone is at the new second zone outlet temperature.
In another embodiment of the present invention, there is a method wherein the first zone gain factor value and the second zone gain factor value are approximately equal when the first zone temperature estimate is between about 20xc2x0 C. and about 28xc2x0 C.
In another embodiment of the present invention, there is a method wherein the first zone gain factor value and the second zone gain factor value vary inversely in relation to changing first zone temperature estimates between at least the range from about 10xc2x0 C. to about 20xc2x0 C. and between at least the range from about 28xc2x0 C. to about 35xc2x0 C.
In another embodiment of the present invention, there is a method wherein the first zone gain factor value decreases with increasing first zone temperature estimates below about 20xc2x0 C. and increases with increasing first zone temperature estimates above about 28xc2x0 C.
In another embodiment of the present invention, the method further includes calculating an overset value to be added to the second zone outlet temperature value, the overset value comprising a value based on the second zone target temperature value, the conduction/convection heat transfer coefficient between the cabin and the ambient air, and the mass air flow rate, as adjusted by a value that sets the strength of the overshoot.
In another embodiment of the present invention, there is a method wherein the mass flow rate of the conditioned air provided to the first zone is about the same as the mass flow rate of the conditioned air provided to the second zone.
In another embodiment of the present invention, the method that further includes calculating a minimum mass air flow rate based on the conduction/convection heat transfer coefficient between the cabin and the ambient air, the second zone target temperature value, the ambient air temperature value, the sun load heat flux value for the second zone, the effective glass area for solar load transmission, and a capacity temperature value selected from a group consisting of a constant cooling device temperature and a constant heating device temperature, and wherein the mass air flow rate of the conditioned air delivered to the cabin is based on the calculated minimum mass air flow rate.
In another embodiment of the present invention, there is a method wherein the mass air flow rate of the air delivered to the cabin is limited to a predetermined maximum mass air flow rate above a variable mass flow rate based on predetermined constraints.
In another embodiment of the present invention, the variable mass flow rate is based on predetermined constraints is substantially correlated to various blower voltages, the maximum mass air flow rate is substantially correlated to the blower voltage, and wherein the maximum mass air flow rate is limited to an equivalent blower voltage that is no greater than about 2 volts above the equivalent voltage of the mass air flow rate based on predetermined constraints.
In another embodiment of the present invention, there is a method wherein the conditioned air provided to the cabin from the first zone outlet and the second zone outlet at outlet temperatures and mass flow rates is equal to the determined outlet temperatures and mass flow rates, respectively.
In another embodiment of the present invention, there is a method for automatically controlling the climate in a plurality of climate control zones of a cabin of an automobile comprising at least a first zone and a second zone having a temperature sensor located in a first zone and an conditioned air outlet vent in each of the zones, the method comprising at least utilizing an algorithm relating to at least the equations
ToD=[TGT(D)+(Gexc2x7(TGT(D)xe2x88x92RMd)+Kxc2x7(TGT(D)xe2x88x92Ta)xe2x88x92qs(D)xc2x7GL)/GAxe2x88x92Rxc2x7ToPa]/(1xe2x88x92R)
and
ToP=ToD+([TGT(P)xe2x88x92TGT(D)]xc2x7(1+K/GA)xe2x88x92[qs(P)xe2x88x92qs (D)]xc2x7GL/GA)/(1xe2x88x92R)
where:
ToD=First zone outlet temperature,
ToP=Second zone outlet temperature,
TGT(D)=First zone target temperature,
TGT(P)=Second zone target temperature,
Ge=Gain factor,
RMd=First zone temperature estimate from sensor,
qs(D)=First zone sun load heat flux,
qs(P)=Second zone sun load heat flux,
GL=Effective glass area for solar load transmission,
Ta=Ambient temperature,
GA=Mass air flow rate,
K=Conduction or convection heat transfer coefficient between the cabin and the ambient air,
R=Zone crossover influence factor,
ToPa=The second zone""s true outlet temperature,
(Evaporator Temperature xe2x89xa6ToPaxe2x89xa6Heater Air Outlet Temperature,
the method comprising, automatically determining ToD, ToP, and GA by solving the above equations with predetermined constraints on the relationship of ToD, ToP, and GA; and providing conditioned air to the cabin from the first zone outlet and the second zone outlet at outlet temperatures and mass flow rates correlating to the determined outlet temperatures and mass flow rates.
In another embodiment of the present invention, there is a method wherein
Gexe2x80x2xc2x7(TGT(D)xe2x88x92RMd)/GA
is subtracted from the calculated value of ToP, wherein Gexe2x80x2 is a gain factor less than or equal to Ge.
In another embodiment of the present invention, there is a method wherein Ge and Gexe2x80x2 are approximately equal when the first zone temperature estimate is between about 20xc2x0 C. and about 28xc2x0 C.
In another embodiment of the present invention, there is a method wherein Ge and Gexe2x80x2 vary inversely in relation to changing first zone temperature estimates between at least the range from about 10xc2x0 C. to about 20xc2x0 C. and between at least the range from about 28xc2x0 C. to about 35xc2x0 C.
In another embodiment of the present invention, there is a method wherein Ge decreases with increasing first zone temperature estimates below about 20xc2x0 C. and increases with increasing first zone temperature estimates above about 28xc2x0 C.
In another embodiment of the present invention, there is a method wherein
OverSetxc2x7[1+K/GA]
is added to the value of ToP, where
OverSet=Xxc2x7(TGT(P)xe2x88x92FSet),
where X is a calibration value, and where
FSet=FSet+Yxc2x7(TGT(P)xe2x88x92FSet),
where Y is a multiplier that is arbitrarily set to allow the FSet equation to be utilized in an algorithm that obtains the unity value of FSet by a loop routine.
In another embodiment of the present invention, the method further includes calculating a minimum mass air flow rate from the equation:
GA=Kxc2x7(TGT(P)xe2x88x92Taxe2x88x92qs(P)xc2x7GL/K)/(Capacity Temperaturexe2x88x92TGT(P))
where Capacity Temperature is a value selected from a group consisting of a constant cooling device temperature and a constant heating device temperature, and wherein the mass air flow rate of the conditioned air delivered to the cabin is based on the calculated minimum mass air flow rate.
In another embodiment of the present invention, there is a method wherein the mass air flow rate of the air delivered to the cabin is limited to a predetermined maximum mass air flow rate above a variable mass flow rate based on predetermined constraints.
In another embodiment of the present invention, there is a method wherein the variable mass flow rate based on predetermined constraints is substantially correlated to various blower voltages, the maximum mass air flow rate is substantially correlated to the blower voltage, and wherein the maximum mass air flow rate is limited to an equivalent blower voltage that is no greater than about 2 volts above the equivalent voltage of the mass air flow rate based on predetermined constraints.
In another embodiment of the present invention, there is a method wherein the constraints include human constraint factors that modify thermodynamic constraint factors in the relationship of air flow and the outlet temperatures, and wherein the method further includes repeatedly addressing the constraints in response to incremental changes in variables in the equations to effect a change that will result in a modification of the outlet temperatures.
In another embodiment of the present invention, there is a method wherein the conditioned air provided to the cabin from the first zone outlet and the second zone outlet at outlet temperatures and mass flow rates is equal to the determined outlet temperatures and mass flow rates, respectively.
In another embodiment of the present invention, there is an automatic climate control apparatus for automatically controlling the climate in a plurality of climate control zones of a cabin of an automobile comprising at least a first zone and a second zone, comprising, an air blower adapted to blow conditioned air into the cabin; an air outlet vent in the first zone in fluid communication with the air blower; an air outlet vent in the second zone in fluid communication with the air blower; an air cooling device and an air heating device in fluid communication with the air blower, the first zone vent, and the second zone vent; a temperature sensor located in the first zone adapted to provide a temperature value estimate of the first zone; an electronic processor device comprising a processor and a memory, wherein the memory is adapted to store a plurality of equations, the plurality of equations including equations for the air outlet temperatures and mass flow rates of the first zone outlet and the second zone outlet, the equations being based on variables including, a target temperature value for the first zone and the second zone; a first zone temperature value estimate; an ambient air temperature value; a sun load heat flux value for at least one of the first zone and the second zone; a first zone gain factor value based at least on the first zone temperature value estimate; a conduction/convection heat transfer coefficient between the cabin and the ambient air; an effective glass area for solar load transmission; and a zone air crossover influence factor, wherein the zone air crossover influence factor is a factor based on the blending of the air in the cabin; wherein the electronic processor is adapted to automatically control and adjust the mass flow rate and the temperature of the air being blown from the vents based on the equations as constrained by predetermined constraints on the relationship of the outlet temperatures and air flow.
In another embodiment of the present invention, the apparatus includes a device adapted to vary the amount of air entering the cabin that has passed through or around the air heating device.
In another embodiment of the present invention, the apparatus includes an automobile having an automatic climate control system.
In another embodiment of the present invention, the apparatus is adapted so that the conditioned air provided to the cabin from the first zone outlet and the second zone outlet at outlet temperatures and mass flow rates is equal to the determined outlet temperatures and mass flow rates, respectively.
In another embodiment of the present invention, there is a device for controlling at least one component of a climate control system that controls the climate in a plurality of climate control zones of a cabin of an automobile comprising at least a first zone and a second zone, comprising, a device adapted to receive a signal representing the mass flow rate of conditioned air being blown into the cabin; a device adapted to output a signal to control the heating and cooling of air being blown into the cabin; a device adapted to output a signal to control the mass flow rate of air being blown into the cabin; a device adapted to receive a signal representative of a sensed temperature inside the cabin; a device storing an algorithm based on at least a plurality of equations, the plurality of equations including equations for air outlet temperatures and mass flow rates of first zone outlet and second zone outlet, the equations being based on variables including, a target temperature value for the first zone and the second zone; a first zone temperature value estimate; an ambient air temperature value; a sun load heat flux value for at least one of the first zone and the second zone; a first zone gain factor value based at least on the first zone temperature value estimate; a conduction/convection heat transfer coefficient between the cabin and the ambient air; an effective glass area for solar load transmission; and a zone air crossover influence factor, wherein the zone air crossover influence factor is a factor based on the blending of the air in the cabin; and a device storing a plurality of predetermined constraints on the relationship of the first zone and second zone outlet temperatures and air flow; wherein the control device is adapted to automatically output a signal to control and adjust the mass flow rate and the temperature of the air being blown from the vents based on the equations as constrained by the predetermined constraints on the relationship of the outlet temperatures and air flows.
In another embodiment of the present invention, there is a method for automatically controlling the climate in a plurality of climate control zones of a cabin of an automobile comprising at least a first zone and a second zone having a temperature sensor located in the first zone and a temperature sensor located in the second zone and an conditioned air outlet vent in each of the zones, the method comprising, obtaining a target temperature value for the first zone and the second zone; obtaining temperature value estimates for the first zone and the second zone from the first zone temperature sensor and the second zone temperature sensor respectively; obtaining an ambient air temperature value; obtaining a sun load heat flux value for at least one of the first zone and the second zone; obtaining at least one of a gain factor value based the first zone temperature value estimate and a gain factor value based on the second zone temperature value estimate; automatically determining the outlet temperatures and the mass flow rates of the first zone outlet and the second zone outlet based at least on the above obtained values and on a conduction/convection heat transfer coefficient between the cabin and the ambient air, an effective glass area for solar load transmission, a zone air crossover influence factor, and predetermined constraints on the relationship of the outlet temperatures and air flow; wherein the zone air crossover influence factor is a factor based on the blending of the air in the cabin; and, providing conditioned air to the cabin from the first zone. outlet and the second zone outlet at outlet temperatures and mass flow rates correlating to the determined outlet temperatures and mass flow rates.
In another embodiment of the present invention, there is a method wherein the zone air crossover influence factor is variable and depends on an air distribution mode.
In another embodiment of the present invention, there is a method wherein the mass flow rate of the conditioned air provided to the first zone is about the same as the mass flow rate of the conditioned air provided to the second zone.
In another embodiment of the present invention, the method further includes calculating a minimum mass air flow rate based on the conduction/convection heat transfer coefficient between the cabin and the ambient air, the second zone target temperature value, the ambient air temperature value, the sun load heat flux value for the second zone, the effective glass area for solar load transmission, and a capacity temperature value selected from a group consisting of a constant cooling device temperature and a constant heating device temperature, wherein the mass air flow rate of the conditioned air delivered to the cabin is based on the calculated minimum mass air flow rate.
In another embodiment of the present invention, there is a method wherein the mass air flow rate of the air delivered to the cabin is limited to a predetermined maximum mass air flow rate above a variable mass flow rate based on predetermined constraints.
In another embodiment of the present invention, there is a method wherein the variable mass flow rate based on predetermined constraints is substantially correlated to various blower voltages, the maximum mass air flow rate is substantially correlated to the blower voltage, and wherein the maximum mass air flow rate is limited to an equivalent blower voltage that is no greater than about 2 volts above the equivalent voltage of the mass air flow rate based on predetermined constraints.
In another embodiment of the present invention, there is a method wherein the conditioned air provided to the cabin from the first zone outlet and the second zone outlet at outlet temperatures and mass flow rates is equal to the determined outlet temperatures and mass flow rates, respectively.
In another embodiment of the present invention, there is a method for automatically controlling the climate in a plurality of climate control zones of a cabin of an automobile comprising at least a first zone and a second zone and having a temperature sensor located in the first zone and a temperature sensor located in the second zone and an air outlet vent in each of the zones, the method comprising at least utilizing an algorithm relating to at least the equations:
ToD=[TGT(D)+(Ge(D)xc2x7(TGT(D)xe2x88x92RMd)+Kxc2x7(TGT(D)xe2x88x92Ta)xe2x88x92qs(D)xc2x7GL)/GA(D)xe2x88x92Rxc2x7ToPa]/(1xe2x88x92R)
and
xe2x80x83ToP=[TGT(P)+(Ge(P)xc2x7(TGT(P)xe2x88x92RMp)+Kxc2x7(TGT(P)xe2x88x92Ta)xe2x88x92qs(P)xc2x7GL)/GA(P)xe2x88x92Rxc2x7ToDa]/(1xe2x88x92R)
where:
ToD=First zone outlet temperature,
ToP=Second zone outlet temperature,
TGT(D)=First zone target temperature,
TGT(P)=Second zone target temperature,
Ge(D)=Gain factor based on a first zone temperature value estimate,
Ge(P)=Gain factor based on a second zone temperature value estimate,
RMd=First zone temperature estimate from sensor,
RMp=Second zone temperature estimate from sensor,
qs(D)=First zone sun load heat flux,
qs(P)=Second zone sun load heat flux,
GL=Effective glass area for solar load transmission,
Ta=Ambient temperature,
GA(D)=Mass air flow rate of the first zone,
GA(P)=Mass air flow rate of the second zone,
K=Conduction or convection heat transfer coefficient between the cabin and the ambient air,
R=Zone crossover influence factor,
ToPa=The second zone""s true outlet temperature,
(Evaporator Temperature xe2x89xa6ToPaxe2x89xa6Heater Air Outlet Temperature,
ToDa=The first zone""s true outlet temperature,
(Evaporator Temperature xe2x89xa6ToDaxe2x89xa6Heater Air Outlet Temperature,
the method comprising:
automatically determining ToD and ToP, and GA by solving the above equations with predetermined constraints on the relationship of ToD, ToP, GA(D) and GA(P); and
providing conditioned air to the cabin from the first zone outlet and the second zone outlet at outlet temperatures and mass flow rates correlating to the determined outlet temperatures and mass flow rates.
In another embodiment of the present invention, there is a method wherein the conditioned air provided to the cabin from the first zone outlet and the second zone outlet at outlet temperatures and mass flow rates is equal to the determined outlet temperatures and mass flow rates, respectively.
In another embodiment of the present invention, there is a method wherein GA(D) is equal to or about equal to GA(P).
In another embodiment of the present invention, there is a method wherein Ge(D) is equal to or about equal to Ge(P).
In another embodiment of the present invention, the method further includes calculating a minimum mass air flow rate from the equation:
GA(D/P)=Kxc2x7(TGT(P)xe2x88x92Taxe2x88x92qs(P)xc2x7GL/K)/(Capacity Temperaturexe2x88x92TGT(P))
where Capacity Temperature is a value selected from a group consisting of a constant cooling device temperature and a constant heating device temperature, and wherein the mass air flow rate of the conditioned air delivered to the cabin is based on the calculated minimum mass air flow rate.
In another embodiment of the present invention, there is a method wherein the mass air flow rate of the air delivered to the cabin is limited to a predetermined maximum mass air flow rate above a variable mass flow rate based on predetermined constraints.
In another embodiment of the present invention, there is a method wherein the variable mass flow rate based on predetermined constraints is substantially correlated to various blower voltages, the maximum mass air flow rate is substantially correlated to the blower voltage, and wherein the maximum mass air flow rate is limited to an equivalent blower voltage that is no greater than about 2 volts above the equivalent voltage of the mass air flow rate based on predetermined constraints.
In another embodiment of the present invention, there is an automatic climate control apparatus for automatically controlling the climate in a plurality of climate control zones of a cabin of an automobile comprising at least a first zone and a second zone, comprising: an air blower adapted to blow conditioned air into the cabin; an air outlet vent in the first zone in fluid communication with the air blower; an air outlet vent in the second zone in fluid communication with the air blower; an air cooling device and an air heating device in fluid communication with the air blower, the first zone vent, and the second zone vent; a temperature sensor located in the first zone adapted to provide a temperature value estimate of the first zone; an electronic processor device comprising a processor and a memory, wherein the memory is adapted to store a plurality of equations, the plurality of equations including equations for the air outlet temperatures and mass flow rates of the first zone outlet and the second zone outlet, the equations being based on variables including: a target temperature value for the first zone and the second zone; a first zone temperature value estimate; an ambient air temperature value; a sun load heat flux value for at least one of the first zone and the second zone; a first zone gain factor value based at least on the first zone temperature value estimate; a conduction/convection heat transfer coefficient between the cabin and the ambient air; an effective glass area for solar load transmission; and a zone air crossover influence factor, wherein the zone air crossover influence factor is a factor based on the blending of the air in the cabin; wherein the electronic processor is adapted to automatically control and adjust the mass flow rate and the temperature of the air being blown from the vents based on the equations as constrained by predetermined constraints on the relationship of the outlet temperatures and air flow.
In another embodiment of the present invention, there is a method wherein the first zone is a driver zone and the second zone is the passenger zone.
In another embodiment of the present invention, there is an apparatus wherein the first zone is a driver zone and the second zone is the passenger zone.